1. Technical Field
The present invention relates to a face region detecting device, method, and computer readable recording medium, and in particular, relates to a face region detecting device, method, and computer readable recording medium which detect the position of a predetermined region of a face from an image in which the face is captured.
2. Related Art
There have conventionally been known dozing state detecting devices which, on the basis of eye positions which were measured a previous time, set eye search regions, and if eyes are found within the eye search regions, consider them to be the same as those which were found the previous time (Japanese Patents Nos. 3312562, 3444115).
There is also known an eye position detecting device which detects the position of the nose, and sets eye search regions by using the detected nose position as the reference (Japanese Patent Application Laid-Open (JP-A) No. 2000-67225).
Further, there is known an eye state detecting device which investigates the vertical direction distance between the nose or an eyebrow or the like and an upper eyelid, and judges whether or not an eye is being detected accurately (JP-A No. 2001-307076).
However, in a case in which the eye search regions are set on the basis of the eye positions which were measured the previous time as described above, if the face moves greatly to the left or right, the eyes will come out of the set eye search regions, and there is therefore the problem that the eyes cannot be detected.
Further, in a case in which the eye search regions are set by using the detected nose position as the reference as described above, there is the problem that, if plural eye candidates are found within the eye search region, complex processing is needed in order to detect the position of the eye.
Moreover, in a case in which the vertical direction distance between the nose or the eyebrow or the like and the upper eyelid is investigated as described above, because the positional relationship between the position of the nose or the eyebrow and the upper eyelid is investigated only in the vertical direction, there is the problem that the eye cannot be detected correctly if the face moves toward the left or right.